All 12 faced charges of violating the Lacey Act, a federal crime of transporting illegally killed animals across state lines.

All 12 men were clients of Camp Lone Star, a deer hunting service in Comanche County.

Dubbed Operation Cimarron, the multi-year investigation involved more than 5,000 man hours for game wardens from Kansas, Texas and the U.S. Fish and Wildlife Service.

John Brooks, U.S. Fish and Wildlife special agent in charge of the ongoing case, said it's probably the largest trophy deer poaching case in U.S. history.

Game wardens have confiscated more than 100 deer antlers or mounts. Up to 60 clients could eventually face charges.

Investigations found Camp Lone Star staff and clients illegally shot deer out of season, shot them with rifles during archery season and shot them after dark with the use of spotlights and night-vision optics. Clients also put illegal permits on deer and shot over the state-mandated limit of one buck per year.

Earlier this summer Camp Lone Star owner James Butler Jr., of Martinsville, Texas, was sentenced to 3 1/2 years in jail and $50,000 in fines and restitution. He pleaded guilty to several poaching charges and a charge of obstruction of justice.

His brother Marlin, also of Martinsville, was ordered to serve 2 1/4 years in jail and pay $20,000 in fines and restitution for a variety of charges.

The Butlers are appealing their sentences.

The crimes occurred between 2005 and 2008. Clients paid $2,500 to $5,500 for their hunts at Camp Lone Star.